Search results for "Matrix"
showing 10 items of 3205 documents
Veränderungen der extrazellulären Matrix in der Venenwand — Ursache der primären Varikosis?
2000
Die kontraren Theorien zur Entstehung der primaren Varikosis fuhrten zur molekularbiologischen Untersuchung der Venenwand, genauer der extrazellularen Matrix. Das Ziel war, die Matrixexpression zu quantifizieren und die pathologischen Veranderungen der Venenwand mit der klappenorientierten Stadieneinteilung der Varikosis zu vergleichen, um so Hinweise auf eine primare Ursache der Varizenbildung zu erhalten.
Inverse eigenvalue problem for normal J-hamiltonian matrices
2015
[EN] A complex square matrix A is called J-hamiltonian if AT is hermitian where J is a normal real matrix such that J(2) = -I-n. In this paper we solve the problem of finding J-hamiltonian normal solutions for the inverse eigenvalue problem. (C) 2015 Elsevier Ltd. All rights reserved.
Analytic energy gradients for the spin-free exact two-component theory using an exact block diagonalization for the one-electron Dirac Hamiltonian.
2011
We report the implementation of analytic energy gradients for the evaluation of first-order electrical properties and nuclear forces within the framework of the spin-free (SF) exact two-component (X2c) theory. In the scheme presented here, referred to in the following as SFX2c-1e, the decoupling of electronic and positronic solutions is performed for the one-electron Dirac Hamiltonian in its matrix representation using a single unitary transformation. The resulting two-component one-electron matrix Hamiltonian is combined with untransformed two-electron interactions for subsequent self-consistent-field and electron-correlated calculations. The "picture-change" effect in the calculation of p…
A chain of solvable non-Hermitian Hamiltonians constructed by a series of metric operators
2021
We show how, given a non-Hermitian Hamiltonian $H$, we can generate new non-Hermitian operators sequentially, producing a virtually infinite chain of non-Hermitian Hamiltonians which are isospectral to $H$ and $H^\dagger$ and whose eigenvectors we can easily deduce in an almost automatic way; no ingredients are necessary other than $H$ and its eigensystem. To set off the chain and keep it running, we use, for the first time in our knowledge, a series of maps all connected to different metric operators. We show how the procedure works in several physically relevant systems. In particular, we apply our method to various versions of the Hatano-Nelson model and to some PT-symmetric Hamiltonians.
A recap on Linear Mixed Models and their hat-matrices
2017
This working paper has a twofold goal. On one hand, it provides a recap of Linear Mixed Models (LMMs): far from trying to be exhaustive, this first part of the working paper focusses on the derivation of theoretical results on estimation of LMMs that are scattered in the literature or whose mathematical derivation is sometimes missing or too quickly sketched. On the other hand, it discusses various definitions that are available in the literature for the hat-matrix of Linear Mixed Models, showing their limitations and proving their equivalence.
Effect of Oral Physiology Parameters on In-Mouth Aroma Compound Release Using Lipoprotein Matrices: An In Vitro Approach
2019
Temporal aroma compound release during eating is a function of the physicochemical properties of the food matrix, aroma compounds, and oral physiology of individuals. However, the influence of each parameter on the release of each aroma component should be clarified. Two flavored lipoprotein matrices varying in composition were chewed in a chewing simulator that reproduced most of the physiological functions of the mouth. Aroma compound releases (butanoic acid, 2-heptanone, ethyl butyrate, 3-octanone, and 2-nonanone) were followed in real time by direct connection of the device to APCI-MS (atmospheric pressure chemical ionization mass spectrometry). Each oral parameter was controlled and de…
Quantitative determination of trichothecenes in breadsticks by gas chromatography-triple quadrupole tandem mass spectrometry.
2014
Breadsticks are pencil-sized sticks of dry bread widely consumed as a pre-meal appetiser. They are basically wheat-based snacks, which makes them a good matrix to evaluate mycotoxin contamination, since wheat is very susceptible to fungal attack. In this sense, the fast, selective and sensitive gas chromatography-triple quadrupole tandem mass spectrometry (GCQqQ- MS/MS) method proposed here allows simultaneous determination of deoxynivalenol (DON), 3-acetyldeoxynivalenol, fusarenon-X, diacetoxyscirpenol, nivalenol, neosolaniol, HT-2 and T-2 toxin in breadsticks after QuEChERS extraction and clean-up. The performance of the method was assessed with respect to European Commission Regulations …
Perlecan Maintains the Integrity of Cartilage and Some Basement Membranes
1999
Perlecan is a heparan sulfate proteoglycan that is expressed in all basement membranes (BMs), in cartilage, and several other mesenchymal tissues during development. Perlecan binds growth factors and interacts with various extracellular matrix proteins and cell adhesion molecules. Homozygous mice with a null mutation in the perlecan gene exhibit normal formation of BMs. However, BMs deteriorate in regions with increased mechanical stress such as the contracting myocardium and the expanding brain vesicles showing that perlecan is crucial for maintaining BM integrity. As a consequence, small clefts are formed in the cardiac muscle leading to blood leakage into the pericardial cavity and an ar…
Evaluation of a novel biomarker of type XXVIII collagen formation, PRO-C28, in samples from cancer and heart failure with preserved ejection fraction…
2020
Increased turnover of extracellular matrix proteins is seen in many different diseases and is an underlying and driving feature of pathogenesis. An increased ratio of formation over degradation of extracellular matrix proteins, such as collagens, leads to accumulation of proteins in the tissues, ultimately impairing organ function. Understanding how this balance is regulated is key to providing deeper insight into high extracellular matrix turnover diseases. Type XXVIII collagen is a novel collagen with limited information available in relation to expression, tissue prevalence and clinical implication. We generated a novel, technically robust ELISA to measure a C-terminal fragment of type X…
New Results from the NUMEN Project
2020
NUMEN aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. First evidence about the possibility to get quantitative information about NME from experiments is found for the (18O,18Ne) and (20Ne,20O) reactions. Moreover, to infer the neutrino average masses from the possible measurement of the half-life of 0νββ decay, the knowledge of the NME is a crucial aspect. The key tools for this project are the high resolution Superconducting Cyclotron beams and the MAGNEX magnetic sp…